The invention concerns to area of nonlinear integrated and fiber optics, to be exact to area completely of optical modulators and switches.
Use of devices is heretofore-known on the basis of Faraday effect, including an optical element passing optical radiation, surrounded by the solenoid for creation of a variable magnetic field (e.g., M. Berwick, J. D. C. Jones, D. A. Jackson xe2x80x9cAlternating-current measurement and noninvasive data ring utilizing the Faraday effect in a closed-loop fiber magnetometerxe2x80x9d, xe2x80x9cOptics lettersxe2x80x9d, v.12, p.4, 1987).
The heretofore-known modulator which is the closest to the suggested modulator is the modulator on the basis of Faraday effect or magneto-optical Kerr effect, containing consistently mounted in a course of a beam an optical element from magneto-optical material, on which the modulating magnetic field acts, and analyzer (S. Gonda, D. Seko xe2x80x9cOptoelectronics in questions and answersxe2x80x9d, Leningrad, Energoatomizdat, 1989, with pp.28-31). Shortcoming of this modulator is a small angle of turn of a polarization plane at small amplitude of a current, and in consequence a small level of modulation, or necessity, of use of a current with the large amplitude. For achievement enough large angles of the turn (of a polarization plane) ensuring an appreciable level of modulation ( greater than 20%), the solenoids with a plenty of coils, or large amplitudes of a current (about 1 A and more), or and that and another are required. A direct consequence of it is the low speed of operation. Use ferromagnetics in magneto-optical element s, as a rule, results in large losses. Shortcoming of modulators on the basis of magneto-optical Kerr effect is restriction on extreme small value of magnetization of domains determining maximal density of recording and/or reading the information. This results in impossibility of reduction of the sizes of the domains to below extreme allowable value, and thus limits density of record.
In the heretofore-known technical decisions the increase of a level of modulation (at moderate currents) is achieved by increase of the optical course of a beam within (magneto) optical element due to repeated reflection from end faces of the optical element (S. Gonda, D. Seko xe2x80x9cOptoelectronics in questions and answersxe2x80x9d, Leningrad, Energoatomizdat, 1989, pp. 126-127), or increase of length of the optical element as such made as fiber-optic waveguide (S. N. Antonov, S. N. Bulyuk, V. M. Kotov xe2x80x9cFaraday optical fiber gauge of a magnetic fieldxe2x80x9d, xe2x80x9cQuantum electronicsxe2x80x9d, 18, No. 1, 1991, pp.139-141). Both in that, and in the other case optical radiation losses grow considerably; besides the modulating variable current, passed through the solenoid, should be strong enough.
The technical result of the invention is expressed in sharp amplification of Faraday effect and achievement of a high level of modulation of optical radiation at rather small amplitudes of a current, and consequently, high speed of operation and low losses, and also in a possibility of reading of the information at higher density of record.
The put task is solved by that the modulator on the basis of Faraday effect, containing optically connected magneto-optical element passing optical radiation and separator of radiations of various polarizations, thereto the magneto-optical element consists of an optical element made from magneto-optical material, and the means creating a variable magnetic field in it, in addition is provided with a nonlinear-optical element located between the magneto-optical element and the separator of radiations of various polarizations.
For the even greater increase of a level of modulation the nonlinear-optical element has a birefringence and/or is made from a magneto-optical material and/or is made from optically active material.
In specific case, most preferable for constructive performance, the nonlinear-optical element is made as the nonlinear-optical waveguide.
Nonlinear-optical waveguide must be made with possibility of propagation in it at least two unidirectional distributively coupled waves of orthogonal polarizations, So in the most preferable case the nonlinear-optical waveguide has a birefringence and/or is made from a magneto-optical material and/or is made from optically active material.
A length of the nonlinear-optical waveguide is not less than the length, which is necessary for switching or transfer at least 10% of a power from one of unidirectional distributively coupled waves with mutually orthogonal polarizations to other unidirectional distributively coupled wave with orthogonal polarization, thereto the length of the nonlinear-optical waveguide, which is necessary for switching or transfer at least 10% of a power of one of said unidirectional distributively coupled waves to another wave with orthogonal polarization, is not exceed the length at which a power of the most attenuated (absorbed) wave from the unidirectional distributively coupled waves of orthogonal polarizations, is attenuated in 20 times or less.
As a rule, a length of the nonlinear-optical waveguide is not less than the length, which is necessary for switching or transfer at least 50% of a power from one of unidirectional distributively coupled waves with mutually orthogonal polarizations to other unidirectional distributively coupled wave with orthogonal polarization, thereto the length of the nonlinear-optical waveguide, which is necessary for switching or transfer at least 50% of a power of one of said unidirectional distributively coupled waves to another wave with orthogonal polarization, is not exceed the length at which a power:of the most attenuated (absorbed) wave from the unidirectional distributively coupled waves of orthogonal polarizations, is attenuated in 10 times.
Thereto, as a rule, the nonlinear-optical waveguide is made as singlemoded.
As a rule, the entrance and/or out put ends (faces). of the nonlinear-optical waveguide have antireflection coverings, in particular, the antireflection coating at ends (faces) of the nonlinear-optical waveguide can be formed lowering factor of reflection of radiation from input and/or output end face up to value no more than 1%.
In a case, when the modulated optical radiation is not polarized, or for, increase of a degree of laser radiation polarization. the modulator in addition contains a polarizer placed before the magneto-optical element.
In special cases the polarizer, mounted before the magneto-optical element, and/or separator of radiations of various polarizations, mounted after the nonlinear-optical waveguide in the course of the radiation beam, is made as a polaroid, or a polarizing prism, or a birefringent prism, or a directional coupler, separating radiations of different polarization, or a polarizer on the basis of single optical waveguide.
For choice and maintenance of the optimum difference between phases of the orthogonally polarized waves, the modulator in addition contains a birefringent element located between said magneto-optical and nonlinear-optical elements. It operates as phase compensator or phase controller.
In special cases the birefringent element is made as an electrooptical crystal supplied with electrical contacts, or waveguide from an electro-optical material supplied with electrical contacts, or phase plate, or a birefringent waveguide, or acousto-optic crystal, or a waveguide from acousto-optic material. For elimination of return influence of the radiations reflected from ends faces of the nonlinear-optical waveguide and other optical elements of the device on the source of optical radiation and the nonlinear-optical waveguide, before the magneto-optical element or at the output of the modulator the optical isolator is mounted; in particular, the optical isolator is made as an optical waveguide.
In specific case the function of separator of waves of various polarizations the nonlinear-optical waveguide as such or the optical isolator mounted at the output of the nonlinear-optical waveguide carries out.
As a rule, the means creating variable magnetic field, is made as the solenoid.
In special cases the nonlinear-optical waveguide is made from a semiconductor doped glass.
In special cases the nonlinear-optical waveguide is made as fiber-optic waveguide, in particular, as birefringent fiber-optic waveguide made from a semiconductor doped glass.
In specific case for increase of efficiency of input/output of radiation on entrance and/or a exit end face of the optic waveguide the lens can be formed and/or a gradan is mounted.
In special cases the magneto-optical element is connected to a nonlinear-optical element made as fiber-optic waveguide, by optical connector or by soldering or by welding or by splice or by glue or by means of tiny mechanical connector.
To provide the compactness of the device and its miniaturizing the magneto-optical element and nonlinear-optical element (made as optic waveguides) are made as one united optic waveguide; or the magneto-optical element, nonlinear-optical element (made as optic waveguide) and the separator of waves of various polarizations, representing waveguide polarizer, are made as one optic waveguide; or the modulator in addition contains an birefringent optical waveguide located between the magneto-optical element and nonlinear-optical element waveguide, and the magneto-optical element, the birefringent optical waveguide, the nonlinear-optical waveguide and separator of radiations various polarizations, representing waveguide polarizer, are made as one united optic waveguide.
In particular, to provide for compactness of the device and its miniaturizing the magneto-optical element and nonlinear-optical element (made as fiber-optic waveguides) are made as one united fiber-optic waveguide; or the magneto-optical element, nonlinear-optical element (made as fiber-optic waveguide) and the separator of waves of various polarizations, representing waveguide polarizer, are made as one fiber-optic waveguide; or the device in addition contains an birefringent optical waveguide located between the magneto-optical element and nonlinear-optical element waveguide, and the magneto-optical element, the birefringent optical waveguide, the nonlinear-optical waveguide and separator of radiations various polarizations, representing waveguide polarizer, are made as one united fiber-optic waveguide.
In the other special case preferable to constructive performance, the nonlinear-optical waveguide is made on the basis of semiconductor layered MQW-type structure with alternating layers containing at least two heterotransition, and the nonlinear-optical waveguide is made with an opportunity of distribution in it two unidirectional distributively coupled waves of various (as a rule with mutually orthogonal) polarizations, wavelength xcexr of one-photon resonance and/or two-photon exiton resonance and/or band-gap resonance and/or half-band-gap resonance in the semiconductor structure of nonlinear-optical waveguide satisfies to the inequality 0.5xcexrxe2x89xa6xcexxe2x89xa61.5xcexr, where xcex is wavelength of at least one optical radiation entered into the nonlinear-optical waveguide.
In particular, the effective switching is reached when the nonlinear-optical waveguide is oriented relative to a vector of polarization of optical radiation entered the nonlinear-optical waveguide, in such a way that the vectors of an electrical field of the linearly polarized optical radiation entered the nonlinear-optical waveguide, or axis of an ellipse of polarization elliptically of the polarized optical radiation entered the nonlinear-optical waveguide, are directed at angle "ugr", xe2x88x9215xc2x0 less than "ugr" less than 15xc2x0 to  less than  less than fast greater than  greater than  and/or to  less than  less than slow greater than  greater than  axes of the nonlinear-optical waveguide. In particular, when the nonlinear-optical waveguide is oriented relative to a vector of polarization of optical radiation entered the nonlinear-optical waveguide, in such a manner that the vectors of an electrical field of the linearly polarized optical radiation entered the nonlinear-optical waveguide, or axis of an ellipse of polarization of the elliptically polarized optical radiation entered the nonlinear-optical waveguide, coincides with  less than  less than fast greater than  greater than  and/or  less than  less than slow greater than  greater than  axes of the nonlinear-optical waveguide.
The effective switching is reached also in case, when the nonlinear-optical waveguide is oriented relative to a vector of polarization of optical radiation entered the nonlinear-optical waveguide, in such a manner that the vectors of an electrical field of the linearly polarized optical radiation entered the nonlinear-optical waveguide, or axis of an ellipse of polarization elliptically of the polarized optical radiation entered the nonlinear-optical waveguide, are directed at a angle 30xc2x0 less than xcex1 less than 60xc2x0 to  less than  less than fast greater than  greater than  and/or to  less than  less than slow greater than  greater than  axes of the nonlinear-optical waveguide. In particular, when the nonlinear-optical waveguide is oriented relative to a vector of polarization of optical radiation entered in the nonlinear-optical waveguide, in such a manner that the vectors of an electrical field of the linearly polarized optical radiation entered in the nonlinear-optical waveguide, or axis of an ellipse of polarization elliptically of the polarized optical radiation entered the nonlinear-optical waveguide, are directed at a angle 45xc2x0 to  less than  less than fast greater than  greater than  and/or to  less than  less than slow greater than  greater than  axes of the nonlinear-optical waveguide.
For increase of efficiency of inodulation the nonlinear-optical waveguide is supplied with contacts for passing an electrical current through it; as a rule, the device contains a current source connected to electrical contacts of the nonlinear-optical waveguide; as a rule, the electrical current source is a constant current source providing the electrical current across the nonlinear-optical waveguide in operation (in service) with values from 0.5 mA to 10 mA, thereto the current spread from an average value in time does not. exceed 0.1 mA.
In particular, the semiconductor structure is made as alternating layers GaAs/AlxGa1xe2x88x92xAs, or InxGa1xe2x88x92xAs/InP, or In1xe2x88x92xGaxAsyP1xe2x88x92y/In1xe2x88x92xxe2x80x2Gaxxe2x80x2Asyxe2x80x2P1xe2x88x92yxe2x80x2, where xxe2x89xa0xxe2x80x2 and/or yxe2x89xa0yxe2x80x2, or CdSe1xe2x88x92xSx/CdSe or InAs1xe2x88x92xSbx/InAs, or PbSxSe1xe2x88x92x/PbSe, or GexSi1xe2x88x92x/Si or alternating layers of other semiconductor materials.
As a rule, the input and/or output ends (faces) of the nonlinear-optical waveguide have antireflection coverings, in particular, the anti-reflected covering at ends (faces) of the nonlinear-optical waveguide can be formed lowering factor of reflection of radiation from entrance and/or output end face up to value no more than 1%.
To increase an efficiency of an input/output of radiation into the nonlinear-optical waveguide the optical elements for the input/output of radiation (hereinafter referred to as  less than  less than input/output elements greater than  greater than ) are mounted accordingly at input and/or an output of the nonlinear-optical waveguide, thereto the input/output elements are mounted relative to the nonlinear-optical waveguide with accuracy provided by their positioning by luminescent radiation of the nonlinear-optical waveguide, arising at passing electrical current through it.
The positioning and/or mounting input and/or output elements, made as objectives, relative to the nonlinear-optical waveguide is accomplished up until formation of collimated optical radiation beam outside (beyond) the said objectives. As a rule the collimated optical radiation beam has cylindrical symmetry.
In specific case to increase efficiency of radiation input/output the input/output elements are made as objectives, consisting from a cylindrical lens and/or gradan; as a rule, the surfaces of cylindrical lenses and/or gradans are clarified (antireflection coated).
In the other special case to increase the radiation input/output efficiency the input/output elements are made as input and/or output optical waveguides .(hereinafter referred to as  less than  less than input/output waveguides greater than  greater than ); as a rule, on input and/or output end face of the input and/or output optical waveguide the cylindrical lens and/or parabolic lens and/or conic lens is formed and/or a gradan is mounted, as a rule, input and/or output end faces of said waveguides and/or gradans are antireflection coated.
In special cases input waveguide contains waveguide connector, which can be made as at least one Y-connector or a directional coupler, in this case at least part of one input branch of the waveguide connector is the magneto-optical element made from magneto-optical material and placed in the solenoid.
To decrease optical radiation power, necessary for effective operation of the suggested modulator and to increase a depth of modulation the modulator in addition contains at least one Peltier element, one side of which is in thermal contact with the nonlinear-optical waveguide and at least by one sensor of temperature, thereto the sensors of temperature and Peltier element can electrically be connected to a temperature controller (regulator) of and/or to the temperature stabilizer.
Under this in the quality of said sensor of temperature they use a thermistor, and/or a thermocouple, and/or a sensor in the form of integrated circuit.
The modulator in addition contains in special cases at least one semiconductor laser and/or the laser module.
For a possibility of orientation of xe2x80x9cfastxe2x80x9d and xe2x80x9cslowxe2x80x9d axes of the nonlinear-optical waveguide relative to a electrical field vector of the linearly polarized radiation, or the axes of an ellipse of polarization of the elliptically polarized radiation, the semiconductor laser and/or the laser module, and/or magneto-optical element, and/or the nonlinear-optical waveguide with elements of input and output of radiation, and/or separator of radiations of various polarizations at the output of the device, and/or polarizer, mounted before the magneto-optical element, and/or optical isolator are connected among themselves by optic-fiber connectors and/or sockets providing for opportunity of turn of mentioned optical elements relative to each other around of longitudinal axis of the device.
In specific case they use fiber-optic connectors and/or sockets such as FC/PC.
For reduction of atmosphere fluctuation, noise and jamming at the output of the separator of the waves having different polarizations, the correlator and/or differential amplifier of optical radiation is set.
The separator of said UDCWs can be placed not only at the output of the nonlinear-optical waveguide immediately after (in close proximity to) output of the waveguide but can be removal from it. In some cases such removal separator is preferred.
Firstly it gives additional possibility for secret transmission of information by optical communications, say by air-path optical communications. The total power of all waves leaving the nonlinear-optical waveguide is not change in time and not modulated. But when they separated said UDCWs at the removal end of the optical communication line by means of said separator before the receivers they obtain modulation and amplified information signal.
Secondly it gives additional opportunity to clear the amplified information signal from noise, jamming and casual distortions. For reduction of noise the signals from the output of the separator can feed to the correlator, in which the common, but opposed in phases part of amplification of signals is separated out (by means of electronic differential amplifier) and, thus, noise and atmosphere fluctuations are cut. In other words, the dependences of powers on time of said unidirectional distributively coupled waves, separated after the output of said nonlinear-optical waveguide, are compared and their difference in powers is selected out by means of a correlator and/or electronic differential amplifier.
In other words the dependences of powers on time of said unidirectional distributively coupled waves, separated after the output of said nonlinear-optical waveguide, are compared and their amplified opposite modulation in powers is selected out by means of a correlator and/or differential amplifier.
The jamming cause sin-phase changing in powers of transmitted UDCWs through the atmosphere whereas in suggested device for modulation of optical radiation and transmitting the information the changing in powers of the UDCWs occur in opposite phases. So their difference in powers can be selected out by means of a correlator and/or differential (operation) amplifier. Under this the atmosphere fluctuations and jamming are rejected.
Thus the common part is selected out with taking into account the changing of the UDCWs are in opposite phases.
In special cases the optical element, comprised in magneto-optical element, is made as passing optical radiation, under this the means creating a variable magnetic field in it, is made as the device of moving of an optical element in space, or device of scanning of a beam of modulated radiation over an optical element.
In particular case the suggested modulator is provided with at least one additional focusing objective, e.g. made as a gradan and/or a lens, and mounted before said magneto optical element and/or before said nonlinear-optical element, and/or with at least one collimating objective, e.g. made as a gradan and/or a lens, placed after said magneto optical element and/or before said nonlinear-optical element.
The put task is solved also by that the modulator on the basis of magneto-optical of the Kerr phenomenon, comprising optically connected an optical element having sites of different magnetization and reflecting modulated optical radiation beam, and a separator of radiations of different polarizations. also the modulator is provided with a device for moving said sites of said optical element with different magnetization in space relative to said modulated optical radiation beam, or with a device of scanning said modulated optical radiation beam over the optical element, the modulator additionally contains the nonlinear-optical element, mounted between said optical element and said separator of radiations of different polarizations, thereto said nonlinear-optical element made with possibility of propagation in it at least two unidirectional distributively coupled waves of different polarizations, thereto the nonlinear coefficient of said nonlinear-optical element is larger than the threshold nonlinear coefficient, thereto a length of the nonlinear-optical element is not less than the length, which is necessary for switching or transfer at least 10% of power from one of said unidirectional distributively coupled waves to another unidirectional distributively coupled wave with different polarization, thereto the length of said nonlinear-optical element, which is necessary for switching or transfer at least 10% of power from one of said unidirectional distributively coupled waves to another unidirectional distributively coupled wave with different polarization, is not exceed the length at which power of the most attenuated wave, from said unidirectional distributively coupled waves of different polarizations, is attenuated by a factor 20 or less.
In more preferable case the length of the nonlinear-optical waveguide is not less than the length, which is necessary for switching or transfer at least 50% of a power from one of unidirectional distributively coupled waves with mutually orthogonal polarizations to other unidirectional distributively coupled wave with orthogonal polarization, thereto the length of the nonlinear-optical waveguide, which is necessary for switching or transfer at least 50% of a power of one of said unidirectional distributively coupled waves to another wave with orthogonal polarization, is not exceed the length at which a power of the most attenuated (absorbed) wave from said unidirectional distributively coupled waves of orthogonal polarizations, is attenuated by a factor 10.
In even more preferable case the length of the nonlinear-optical waveguide is not less than the length, which is necessary for switching or transfer more 90% of a power from one of unidirectional distributively coupled waves with mutually orthogonal polarizations to other unidirectional distributively coupled wave with orthogonal polarization, thereto the length of the nonlinear-optical waveguide, which is necessary for. switching or transfer more 90% of a power of one of said unidirectional distributively coupled waves to another wave with orthogonal polarization, is not exceed the length at which a power of the most attenuated (absorbed) wave from said unidirectional distributively coupled waves of orthogonal polarizations, is attenuated by a factor 10.
As a rule said unidirectional distributively coupled waves of different polarizations are the unidirectional distributively coupled waves having mutually orthogonal polarizations.
Usually said optical element is made as the form of disk, or in the form of plate.
As a rule, the suggested modulator is provided with at least one additional focusing objective, e.g. made as a gradan and/or a lens, and mounted before said magneto optical element and/or before said nonlinear-optical element, and/or with at least one collimating objective, e.g. made as a gradan and/or a lens, placed after said magneto optical element and/or before said nonlinear-optical element.
For the even greater increase of a level of modulation the nonlinear-optical element has birefringence and/or is made from magneto-optical material or optically active material.
In specific case, most preferable for constructive performance the nonlinear-optical element is made as the nonlinear-optical waveguide.
In a case, when the modulated optical radiation is not polarized, or for increase of a degree of polarization of laser radiation, the modulator in addition contains a polarizer located before the magneto-optical element.
For choice and maintenance of an optimum difference in phases of the orthogonal polarized waves the phase equaliser (compensator) and/or phase controller is mounted between the magneto-optical and the nonlinear-optical elements; in particular, the phase compensator is made as waveguide compensator. For choice and maintenance of an optimum input polarization at the input of nonlinear-optical element the polarization controller may be also used.
As a rule, the phase compensator is made as a birefringent element, placed between the magneto-optical element and the nonlinear-optical elements. Usually birefringent element is made as a birefringent optical waveguide, or a fiber-optic phase compensator, or a fiber polarization controller, or an optical waveguide made from electrooptical material, supplied with electrical contacts, or an electrooptical crystal, supplied with electrical contacts, or a phase plate, or an acousto-optical crystal, or an optical waveguide made from an acousto-optical material.
To eliminate return influence of reflected radiation on a source of optical radiation and the nonlinear-optical waveguide before magneto-optical element or at the output of the modulator the optical isolator is mounted, in particular, the optical isolator is made as optical waveguide.
In that specific case the function of separator of optical radiations having various polarizations the nonlinear-optical waveguide as such or optical isolator mounted at the output of the nonlinear-optical waveguide carries out.
As a rule, the nonlinear-optical waveguide is singlemoded.
In special cases the nonlinear-optical waveguide is made as fiber-optic waveguide.
In special cases the nonlinear-optical waveguide is made as nonlinear fiber-optic waveguide, in particular, as birefringent fiber-optic waveguide from a semiconductor doped glass.
In specific case for increase of efficiency of input/output of radiation on entrance and/or a output end face of the fiber-optic waveguide the lens can be made and/or gradan is mounted.
In special cases the magneto-optical element is connected to a nonlinear-optical element made as fiber-optic waveguide, by optical connectors, or by splice, or by welding, or by glue, or by means of tiny mechanical connector.
In the other special case preferable to constructive performance, the nonlinear-optical waveguide, is made on the basis of semiconductor layered structure such as MQW with alternating layers containing at least two hetero-transition, and the nonlinear-optical waveguide is made with an opportunity of distribution in it two unidirectional distributively coupled waves having various polarizations, and wavelength of one-photon exiton resonance and/or two-photon exiton resonance and/or band-gap resonance and/or half-band-gap resonance in semiconductor layered MQW-type structure of the nonlinear-optical waveguide satisfies to the inequality 0.5xcexrxe2x89xa6xcexxe2x89xa61.5xcexr, where xcex is wavelength of at least one optical radiation entered the nonlinear-optical waveguide.
The more preferable case is that when 0.9xcexrxe2x89xa6xcexxe2x89xa61.1xcexr.
The birefringence of said structure is another clue factor (besides high nonlinear coefficient) of such structure which allow us to realize effective all-optical transistor on the basis of said structure, using self-switching of the UDCWs having orthogonal polarizations.
The effective switching is reached (achieved) in that case, when the nonlinear-optical waveguide is oriented relative to a vector of polarization of optical radiation entered in the nonlinear-optical waveguide, in such a manner that the vectors of an electrical field of the linearly polarized optical radiation entered the nonlinear-optical waveguide, or axis of an ellipse of polarization of the elliptically polarized optical radiation entered the nonlinear-optical waveguide, are directed at an angle of xe2x88x9215xc2x0 less than xcex1 less than 15xc2x0 to  less than  less than fast greater than  greater than  and/or to  less than  less than slow greater than  greater than axes of the nonlinear-optical waveguide. In particular, when the nonlinear-optical waveguide is oriented relative to the vector of polarization of optical radiation entered the nonlinear-optical waveguide, in such a manner that the vectors of an electrical field of the linearly polarized optical radiation entered in the nonlinear-optical waveguide, or axis of the ellipse of polarization of the elliptically polarized optical radiation entered the nonlinear-optical waveguide, coincide with  less than  less than fast greater than  greater than  and/or  less than  less than slow greater than  greater than  axes of the nonlinear-optical waveguide.
The effective switching is reached also in that case, the nonlinear-optical waveguide is orientated relative to a vector of polarization of optical radiation entered the nonlinear-optical waveguide, in such a manner that the vectors of an electrical field of the linearly polarized optical radiation entered the nonlinear-optical waveguide, or axis of an ellipse of polarization of the elliptically polarized optical radiation entered the nonlinear-optical waveguide, are directed at an angle 30xc2x0 less than xcex1 less than 60xc2x0 to  less than  less than fast greater than  greater than  and/or to  less than  less than slow greater than  greater than  axes of the nonlinear-optical waveguide. In particular, when the nonlinear-optical waveguide is orientated relative to the vector of polarization of optical radiation entered the nonlinear-optical waveguide, in such a manner that the vectors of the electrical field of the linearly polarized optical radiation entered the nonlinear-optical waveguide, or axis of an ellipse of polarization of the elliptically polarized optical radiation entered the nonlinear-optical waveguide, are directed at an angle of 45xc2x0 to  less than  less than fast greater than  greater than  and/or to  less than  less than slow greater than  greater than  axes of the nonlinear-optical waveguide.
To increase the efficiency of modulation the nonlinear-optical waveguide is provided with contacts for passing an electrical current through it, as a rule, the modulator contains a current source of a connected to electrical contacts the nonlinear-optical waveguide; as a rule, the source of a current is a precision constant current source providing a current, passed through the nonlinear-optical waveguide in a mode of operation (i.e. in service) with values in the range from 0.5 mA up to 10 mA, thereto the current spread from an average value over the time does not exceed 0.1 mA.
In particular, the semiconductor structure is made as alternating layers GaAs/AlxGa1xe2x88x92xAs, or InxGa1xe2x88x92xAs/InP, or In1xe2x88x92xGaxAsyP1xe2x88x92y/In1xe2x88x92xxe2x80x2Gaxxe2x80x2Asyxe2x80x2P1xe2x88x92yxe2x80x2, where xxe2x89xa0xxe2x80x2 and/or yxe2x89xa0yxe2x80x2, or CdSe1xe2x88x92xSx/CdSe or InAs1xe2x88x92xSbx/InAs, or PbSxSe1xe2x88x92x/PbSe, or GexSi1xe2x88x92x/Si or alternating layers of other semiconductor materials.
For increase of efficiency of an input/output of radiation optical elements of an input/output located accordingly at an input and/or an output of the nonlinear-optical waveguide, and the input and/or output elements are mounted relative to the nonlinear-optical waveguide with accuracy provided by their positioning (adjustment) by luminescent radiation the nonlinear-optical waveguide, arising at passing an electrical current through it.
In that specific case for increase of efficiency of input/output of radiation the elements of input and/or of an output are made as objectives, consisting from a cylindrical lens and/or gradan; as a rule, the surfaces of the cylindrical lenses and/or gradans have antireflection coatings.
In the other special case to increase efficiency of input/output of optical radiation the input and/or output elements are made as input and/or output optical waveguide; as a rule, on input and/or output end face of input and/or output optical waveguide the cylindrical and/or parabolic and/or conic lens is formed and/or a gradan is mounted; as a rule, the input and/or output end faces of the said optical waveguide and/or gradans are antireflection coated.
To decrease optical radiation power, necessary for effective operation of the suggested modulator and to increase a depth of modulation the modulator in addition contains at least one Peltier element, one side of which is in thermal contact with the nonlinear-optical waveguide and at least by one sensor of temperature, thereto the sensors of temperature and Peltier element can electrically be connected to a temperature controller (regulator) of and/or to the temperature stabilizer.
Under this in the quality of said sensor of temperature they use a thermistor, and/or a thermocouple, and/or a sensor in the form of integrated circuit.
The device in addition contains in special cases at least one semiconductor laser and/or the laser module.
For reduction of noise at the output of the nonlinear-optical waveguide the correlator of optical radiation is mounted.